1. Field of the Invention
The present invention relates to an image reading apparatus, a copying apparatus, and an image processing apparatus, which have a function of discriminating a specific original.
2. Related Background Art
Conventionally, various methods associated with recognition of, e.g., a specific original, have been proposed.
Methods of recognizing that an image pattern of an original is defined by a line image, or recognizing a color tone of an image original, have also been proposed.
Furthermore, in another method, a specific mark is printed with a fluorescent ink, which reflects visible light upon radiation of ultraviolet rays onto a specific original itself, so as to identify an original print from copies on the basis of the presence/absence of the fluorescent mark.
However, when these methods are applied to a copying machine, it is difficult to detect a specific original which is located at an arbitrary angle with respect to an arbitrary position on an original table of the copying machine, and hence, it is difficult to prevent forgery.
Even when line image information or a color tone of an original is detected, some normal originals may exhibit equivalent characteristics as those of a specific original, and a normal original may be erroneously determined to be a copy-inhibited original.
Furthermore, in the copying machine which detects a specific original on the basis of the presence/absence of a fluorescent mark, both an arrangement for detecting ultraviolet rays and an arrangement for detecting visible light for a copying operation are required, and the apparatus scale undesirably becomes very large. In addition, the levels of the detected ultraviolet rays and visible light vary depending on individual differences of apparatuses, and it is difficult to achieve precise detection.